Refresh Codemirror when opening fullscreen editor.

* Refresh Codemirror editor upon release of esc key.
* Adding new directive to handle global keyup events.
* Listening on 'keyup' instead of 'keydown'.
  'keydown' triggers lots of times when keep pressing key.
* Delete keydown directive file since it's not used.
Merge pull request #3038 from oskarhane/fix_fullscreen_editor

Browser: Fix fullscreen editor.